Power transmission apparatus



Oct. 29, 1946. G. WALLACH POWER TRANSMISSION APPARATUS- Filed July 19; 1944 6 Sheets-Sheet 1 Inventor GEOFGL' h AL L A CH,

Oct. 29, 1946. G, wALLAc-H 2,410,137

POWER TRANSMI S S ION APPARATUS Filed July 19, 1944 6 Sheets-Sheet 2 Oct. 29, 1946. G. WALLACH POWER TRANSMISSION APPARATUS 6 Sheets-Sheet 3 kl WW mm H Filed July 19, 1944 Inventor 650/? M14 mc B}! Q Ot. 29, 1946. I e. WALLACH 2,410,137

POWER TRANSMI SS ION APPARATUS Filed July 19, 1944 6 Sheets-Sheet 4 I Oct. .29, 1946. G: w c 2,410,137

POWER TRANSM I S S ION APPARATUS Filed July 19, 1944 s Sheets-Shet s Oct. 29, 1946. w c -l 2,410,137

POWER TRANSMISSION APPARATUS Filed July 19, 1944 e SheetS- Sheet G 650/?65 W4 L-LACH,

Patented Oct. 29, 1946 UNITED STATES PATENT OFFICE bia, Canada Application July 19, 1944, Serial No. 545,693

6 Claims.

This invention relates generally to power transmission apparatus, and an important object of the present invention is to provide, in an apparatus of the above kind, an improved planetary type of variable speed hydraulic transmission.

Another important object of the present invention is to provide, in an apparatus of the above kind, a variable speed transmission for forward speeds, and an improved combined differential and reversing gearing for transmitting power from the driven shaft of the transmission to the rear aligned transverse axle sections of a motor vehicle, whereby reverse drive of the vehicle may be effectd in a simple manner and without incorporating the reverse drive in the transmission. This is particularly useful when a hydraulic transmission is employed, as in the present invention, permitting simplification of the transmission.

A more specific object of the present invention is to provide an improved hydraulic transmission of the above kind wherein the sun gear is fixed on the driven shaft, wherein a pair of gear pumps is provided in the transmission casing with one gear of each pump meshing with the sun gear and constituting a planet gear movable with the transmission casingin an orbital path about the sun gear, the pump gears being carried by axes parallel with the driven and driving shafts and fixed to the transmission casing, the trans-- mission casing being fixed on the driving shaft, and manually operable means being provided for controlling the fiow of oil to the gear pumps for varying the stalling action on or resistance to rotation of the pump gears. Thus, if the pump gears are allowed to rotate freely about their axes as they revolve with the transmission housing about the sun gear, no power is transmitted from the driving to the driven shaft. On the other hand, if resistance is offered to rotation tion is to provide a transmission of the above of the pump gears by causing them to pump oil in circuits within the transmission housing, power will be transmitted from the driving shaft to the driven shaft, and the amount of resistance to rotation of the pump gears about their aXes will determine the ratio of rotation between the driving and driven shafts. Oil is supplied to the pumps at the periphery of the housing and controlled by manually operable gates which regulate fiow of the oil from the space between the pumps, thereby varying the amount of oil that must be handled by the pumps, and correspondingly varying the resistance offered to the rotation of the pump gears about their axes.

A further specific object of the present invencharacter, wherein the transmission housing is divided by a partition into a pump chamber and an oil supply chamber, and wherein float valves are provided for controlling the flow of oil from -the oil supply chamber to the pump chamber so as to maintain a predetermined quantity of oil in said pump chamber.

A still further object of the present invention is to provide a transmission of the above kind which is comparatively simple, compact and durable in construction, and so constituted as to insure continued eflicient operation.

Further objects of the invention will become apparent from the following description when considered in connection with the accompanying drawings, and the invention consists'in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the drawings and'claims.

In the drawings, wherein like reference characters indicate corresponding parts throughout the several views- Figure 1 is a fragmentary side elevational view, partly broken away and partly in section, of a driving apparatus for a motor vehicle embodying a transmission and a combined differential and reversing gearing constructed in accordance with the present invention.

Figure 2 is an enlarged transverse section taken substantially on line 2-2 of Figure l and showing the transmission in-front elevation.

Figure 3 is a vertical longitudinal section taken on line 3 -3 of Figure 2.

Figure 4 is a transverse section taken on line 4-4 of Figure 3.

Figure 5 is a transverse section taken on line 5-5 of Figure 3.v

Figure 6 is a transverse section taken on line 6-6 of Figure 3. I

Figure 7 is a fragmentary section taken on line 1-1 of Figure 6.

Figure 8 is a perspective viewof one of the gates for controlling'the flow of oil through the pumps, together with its actuating arm.

Figure 9 is a fragmentary perspective view showing a portion of the rear cover plate of the transmission housing, and illustrating the manner in which said cover plate is provided with float chambers.

Figure 10 is an enlarged perspective view of one of the float valves.

Figure 11 is a fragmentary View, partly diagrammatic, illustrating the manner in which the pump gate actuating pedal may be utilized spam 3 to close the circuit of a solenoid for opening the throttle valve of an engine carburetor so that the engine may be operated with the throttle wide open when the present transmission is in use.

Figure 12 is a fragmentary transverse section taken on line 12-12 of Figure 1.

Figure 13 is a longitudinal section taken on line I3-! 3 of Figure 12.

Figure 14 is a top plan view of the construction shown in Figure 12.

Figure 15 is a fragmentary side elevational view showing the present transmission employed in the driving apparatus for stationary ma: chinery, and

Figure 16 is a section taken substantially on line Iii-46 of Figure 15.

Referrin in detail to the drawings, indicates the motor or driving shaft and 6 the driven shaft, which shafts are operatively connected by means of a variable speed hydraulic transmission constructed in accordance with the present invention. The transmission includes a cylindrical or circular housing 1 provided at its front end with an axial hub 8 keyed. on the rear end of drivin shaft 5, as at 9, and provided with a transverse partition'lll that divides the interior of the housing into a front pump chamber H and a rear oil supply chamber or reservoir 12. The housing has a rear closure plate [3 formed with an internal cylindrical hub M in which is fitted a bearing sleeve that receives the driven shaft 6. The front end of driven shaft 6 projects into the pump chamber 1 I and has a driven or sun gear l6 fixed thereon. Gear pumps .are provided within the chamber H at opposite sides of the housing I, each gear pump including a pair of intermeshing gears or gear pistons I1 and I8 journaled on enlarged stem portions iii of stud bolts 20 fixed in the front wall of the housing 1. The gear l8 of each pump is of larger diameter than the gear I1 thereof and meshes with the sun gear I6. The partition H3 is drawn by nuts on bolts 20 snugly against the rear ends of the enlarged bolt portions #9 and also against an internal annular shoulder 2! provided in the housing 7. Bolts 20 are extended through cover plate I3 and have nuts 22 threaded thereon to secure said cover plate in place. Fitted in the space between. and at the outer sides of the gears of each pump is a block 25 having faces 26 conforming to the contour of the gears l1 and i8 and lying closely adjacent thereto, outer arcuate surfaces of the blocks 25 contacting and conforming to the inner surface of the housing 1. The blocks are doweled and bolted in place, as indicated at 21 and 28, respectively. A space 29 of appreciable size is thus left within the pump chamber H between the pumps, which space is radially divided intermediate the pumps and at opposite sides of the sun gear l6 by means of baffles 39. Thus, the pumps receive the oil at their outer sides or adjacent the periphery of the housing "I and discharge it in opposite directions into the space 29 adjacent the sun gear It, as indicated by dotted arrows. The baffles 30 carry rigid threaded studs 23 and 3! on their rear edges which also project through the partition I!) and respectively have nuts 24 and 32 threaded thereon to secure the baffles in place.

As the oil is maintained at a predetermined pro-per level within the chamber H by a means that will be later described, and as the housing 1 rotates with the driving shaft 5, such oil will be evenly distributed by centrifugal fo-ce in a layer of considerable thickness at the inner peripheral surface of the housing 7 within the outer portions of the space 29. Swinging gates or gate valves 33 are provided in the chamber H at the outer sides of the gears of each pump so as to control the flow of oil to the pumps from the space 29. As shown clearly in Figure 4, the gates 33 are closed by swinging them outwardly so as to contact the peripheral wall of the housing 1 at their outer ends, while the gates 33 are opened by swinging them inwardly toward the adjacent pump gears as shown by dotted lines.

Obviously, if the gates 33 are closed, no oil will be permitted to flow from the space 29 to the pumps, and the pump gears ii and It may rotate freely about their axes l9 so as to revolve with the housing 1 and driving shaft 5 about the sun gear IS without driving the latter or the driven shaft 5. As the gates 33 are opened, however, oil will be permitted to flow to the pumps so that the latter will build up a pressure between the gears thereof that will act to stall or resist rotation of the pump gears about their own axes 199. Naturally, upon the degree of opening of the gates 33 and the amount of stalling imposed upon the pump gears will depend the ratio of speed between the driving and driven shafts 5 and Slowing the speed of rotation of the pump gears about their axes l9 will cause power to be transmitted from shaft 5 to shaft 6, the ratio of drive being dependent upon the degree to which the pump gears are slowed in rotation about their axes I9. Theoretically, if the pump gears are not permitted'to rotate at all on their own axes, the driven shaft will be driven at exactly the same speed as the driving shaft. However, there will be a limited amount of slippage due to the leakage of oil so that the most practical attainment is to succeed in driving the driven shaft at about of the speed of the driving shaft. It is well to point out at this time that the action obtained herein is not similar to that obtained by controlling the output of a pump located within a stationary housing. Instead, the action obtained in this invention is to vary the quantity of oil supplied to and capable of being pumped by the pumps, thereby controlling the amount of pressure that may be built up between the gears of the ,puinpand consequently controlling the degree of stalling of the pump gears or the degree of resistance proper to rotation of the pump gears about their own axes. More particularly, it should be borne in mind that this is had in connection with gear pumps whose gears revolve with a rotary housing keyed on and rotating with the driving shaft.

Secured on and rotatable with the external hub 8 of the housing 1 is the hub of a spider having radial angular arms 35 whose outer ends are directed rearwardly toward the housing 3 and are formed with rearwardly diverging inclined slots 35, the opposed walls of which are grooved as indicated at 37 inFigures 4 and 6. Slidably received in the grooved or undercut slots 36 are ball members 38 provided on corresponding ends of actuating arms 31) secured on and projecting laterally from the forward ends of pintles ll of the gates 33. The pintles 4! are journaled in bearings lz of the housing 1, and the arms Ml have hubs 43 fitted on tapered terminal portions of the pintles El and secured thereon by cap screws M (Figure 2). threaded in axial threaded bores 65 (Figure 8) of the pintles 4|. The hub 34 of the spider is provided with opening provided in the'peripheral volubly positioned a shifting ring 41,; to opposite the ends of the, arms'of a shifting fork 59 carried by a foot-pedal sides of which is pivotedat 48 50 andpivoted'at its upper end,.1as at...5l, to a suitable fixed bracket 52. The arrangement'is such that when the pedal 50 is depressed, shifting 'fork 49 is swung rearwardlyso as to slide the spider rearwardly and cause the arms 49, through the medium of balls 38; to follow the inclination of slots 36. This causes swinging movement of arms 4!) toward shaft 5 and swingingof gates 33 to open position. The'degree'of opening of gates 33, of course, depends upon the distance to which the pedal 50 is depressed, and the parts are returned to normal position by spring 53 acting on lever 49 so as tonormally close the gates 33. -In order to cause the spider 34, 35 to rotate with the housing 1, said spider is provided at opposite sides with supplementalradial arms 54 having openings 55 in their outer ends which slidably receive guide pins 56 that are fixed to and project forwardly from the front wall of housing l directly inwardly of the bolts 28. The grooves 31 are of segmento-spherical form in cross section so as to permit the'ball members 39 to turn therein and thereby allow the arms it to assume different angular positions to which they are moved by the shifting urine spider toward and from the housing].

As shown clearly in Figures 3, 5, and 9, the cover plate I3 jecting annular flange 51"that is cutaway at diametrically opposite points, as" at 58, and that is formed at these points with inwardly pro jecting, channel-shaped float chambers 59 prey vided with rear walls 613 spaced from the adja cent closure plate l3 and openings fil. An L-shaped bracket 62 is "secured to the inner, offset portion of wall 69 ,bviscrews G3, or the like, and directly opposite this L-shaped;

bracket 62 the flange 51 is 'formed with an open}; ing 6L Loosely arranged ineachffloatjchainber is a rectangular, float 65 having a fulcrum lug 68 at its rear end. engaged loosely opening 64 and carried by a bracket 61 flired to the adjacent end of the float, The bracket 6-!- also carries a valve plugEB' arranged to seat against the wall fifl'about the p ni'ng BI to normally close the latter. tilted about the fulcrum lug 66 inwardly by means ofarelatively weak leaf spring 69 attached to' the outer wall, of 'the. float at asgriear; end ans; hearing, at itsforward end, "against the peripheral waiver theh'ousing lfatlthe forward pa is formed with; an inwardly proprovided with inlet in the adjacentv flooding the pump chamber when the transmis-- sion is'not in operation. v In Figure 1, I have shown a driving apparatus of .thekind 'employedin transmitting power from an internal? combustion engine to the rear axle sections of a'jmotor vehicle, such apparatus-utilizing a-variablespeed transmission T constructed in accordance with also acombined differential and reverse gearing T nwhich is-also; constructed in accordance, with the present invention, the gearing T= serving to transmit power to the transversealigned rear axle sections Hand Ila of the vehicle from a longitudinal propeller shaft 12 that is coupled by a universal j oint l thetransmission T. The shaft fi 'is shown as supported by a suitable bearing "l4 mounted on the underside of a transverse framemember 15 of the a vehicle chassis.- "As shownin Figures 1 the gearing T' is of conventional type andcon struction exceptthat the spider for 1 thefspider gearsof the differential carriesja second beveled ring gear 16 in addition to the conventionalbeveled ring gear 16a, ring gear 16a and disposed V l the drive pinion T! of propeller ;shaft 12 from that at which the ordinary r n ear 16a} is dis} posed. Thus, when the pinionll is engagedwith ring gear l 16a,

whi1e,jif the pinion 11 is e gear l6, said rear axle sections driven in a reversedirection.

either desired one of t e r n ears d the. latterlgears are spaced apart a distance slightlylgreater. than tlie diameter of pinion 11,.

and propeller shaft 12 is mounted for limited lateralmovement at its rearend with respect to-the. Thus, I the shaft [2 ex? tendsthrough an opening in the front of housing front wall. ..Thus,;by the provision .of suitable i housingl8 and plate 19, leakage of oil from the housing the float chamber- The oil supply chamber lti' may "be filled with. oil thro'ughfa suitable filler 7 wall of house. ing 1 and normally closed byairemovablef w. plug 10 (Figure.;5 The arrangement; is such that when the housing, I is rotatedfth'e oil will assume a layer adjacent. the innerfperipheral surface of the housing 1." ,At' the.,start .oflthe 0peration, the floats are moved outward by ce'n' trifugal force, and by so doing, 'the lvalve plugs 68 uncover, the openings 5!, permitting "oil'to new from the supply chamber l2 tothe pum pichamber I}. As soon as the quantity of pi; in the pump chamber reaches the desired mark, the front ends of thefloats move inwardly so as to causethe plugsfiS to close openings 6|. ,In; this way, the quantity ofoil in the pump,chamber' is main:

. heq Q tant-. leaf s ri s?? {ins re a a n t.

packing between the contiguous faces of the 18 may be prevented at the opening where the shaft 12 projects into said housing 18. Shaft" is. journaled in a bearing at carried by the plate 8 I and niovable between flanges 82 on -the .front wall of housing-18, asshown in Figure '13. At its upper edge, the plate 19.15 provided with arack 83, and meshing with the teeth of this-rackis a mutilated spur pinion 84 provided on one .end of a lever 85 and pivoted at 86to the front wall of housing 18. A bell crank lever 81 is pivoted at 88 to-the vehicle frame at one side of the shaft 12, and one arm of this bell crank lever is connected by a rod 89 with the lever 85. The other armof lever 81 may be connected by a rod 99with a hand lever within convenient reach of the driver of the motor vehicle.. ,The arrangement is such that whentherod is pulled forwardly mutilated pinion 84 is turned to. pl te "in a d re ti n to.

the present invention and 13 with the driven shaft fi of:

and 12 t '14, mas ive;

the ring gean'lflfacing the t the opposite side-of the rear axle sections'll ,and' 'lla' will be differentiallydriven in .one. direction, ngaged with" the ring H and Na will be I In order to permit} selective engagement of driving pinion. H with drive pinion 11 to engage ring gear 16. On'the other hand, when the rod 90 is moved r'ea'rwardly, the lever 85 is swung in a direction to move drive pinion 11 into mesh with ring gear 16a, thereby causing the rear axle section's H and II a to be driveriin a reverse direction. It will be appar'- ent that by this slight and practical modification of a conventional differential gearing,- the necessity for incorporating reversing mechanism in the variable speed transmission T is eliminated. This results in the production of a. variable speed transmission of the hydraulic type which is of simplified form and only required to provide different speeds of forward travel of the vehicle; When a motor vehicle is equipped witha variable speed transmission constructed in accordance with-thepresent invention, it is desirable to permit the internal combustion engine, which forms the power plant of the vehicle,- to operate with the throttle valve 9| of the e'rig'ir'ie carburetor 92 in fully open position whenever the transmission is brought into operation by opening movement of gates 33. The throttle valve 9|, of course, controls the admission of air through the air intake 93 of the carburetor 92,'and it has an operating lever 94 which is connected inaccordance with the present invention with the core of a solenoid 95. One side of the coil of solenoid 95 is shown grounded as 96, while the other side thereof is connected by a wire 91 with acontact 98 or a circuit maker and breaker.- The contact 98 is carried by the shifting lever or fork 49, and is opposed to another contact 99 fixed to a stationary bracket Hill. The" arrangement is such that when the pedal 50- is depressed, the contact 98 will be engaged with contact 99 so as to close the circuit of the solenoid 9 and thereby cause the latter to fully open the throttle' valve 9| when the gates 33 of the transmission T are swung towardopen position; As shown, a manually operable switch I00 may be interposed in the wire'9'l for rendering the solenoid 95 operative or inoperative at will, depending upon whether or not its-use" is desired. Also, the contact 99 is connected by a wire l0! toonesneer a battery I02, whose other: side is grounded at I03. The circuit ofthe solenoid 95 will be readily traced from this description. 7 I

In Figures and 16, I have shown" the present variable speed transmission I' incorporated in the driv-e for static-nary machinery. in this sort of installation, the driving" motor may cohsist of an electric motor I94" having the housing I of the transmission secured on" the armature thereof. Also; the driven shaft G-m ay be'equipped In' operation, the transmission housing I rotates with the drive shaft 5 so that the oil in the pump chamber H is thrown outwardly and distributed in a uniform layer at the periphery of the transmission housing within the space between the pumps. With the transmission housin'g rotating, and the driven gear l6 stationary, the planetary gears. 18 are caused to rotate, and they, in turn, rotate the cooperating pump gears I? in a manner to pump oil inwardly toward the center of the transmission housing. As no outletis provided for oil thus pumped, except through tolerances in mesh between each pair of pumping gears, an oil pressure is built up, which oil pressure acts on the pump gears to restrain them from rotating on their respective axes. This lends driving ability to the gears 18 instead of just idling around the driven gear it. Thus, if resistance is offered to rotation of the driving gears l8 by the oil pressure, and if such resistance should equal the torque on the driving gears produced by the resistance of the driven gear to rotation, a one to one ratio between driving and driven gears would be the result. If, however, the resistance to rotation of the driven gear increases, the driving gears will rotate on their own axes and at the same time will move aroundthe driven gear to a variable extent, thus increasing the ratio between the driving and driven gears. The increased speed of rotation of the driving gears on their own axes will result in oil being pumped at a higher rate, thus tending to maintain the necessary oil pressure to overcome the high resistance offered by the driven gear. When the higher oil pressure is not demanded, the reverse action takes place. In order to drive the sun gear 16 on the driven shaft 6, the fork 49 is moved with a suitable coupling element Hi5, by means of which said driven shaft may becouple i p o the shaft of the machinery which istobe driven. In this sort of installation, the shifti gj fork'fisaf is extended downwardly fromthe drive-shaftand has its lower and mounted for rocking movement in a socket iiifiof the moto'rb'as'e "H1 71 gnarl-sverse horizontal shaft [G8 is journal'od in a bracket 19 rigidly mounted on the base'HlE and this shaft Hi8 carries an eccentric ll'il rotatable in an eccentric strap portion H lofthe shifting fork 49a; A'tone end, shaft Hi8 iseduipped with a hand wheel H2 to facilitate sienna-1 turning thereof. Thus, by' turning shaft lgl8l eccntric I l'li ma'y be turned to shift theforli illd arid thereby opera-t6 thes'p'ider 34-, 35 for openifig'o'rclo'sing the gates 33 of the transmission. '9ther wi'se,[the transmission of this embodiment-is constructed exactly the same as" that already" described in' connection wan Figures 1 to 10, inclusive;

to open the gates 33 to the desired extent, permitting the accumulated oil between the pumps to flow to the latter. Pressure is then built up between the gears of the pumps, the oil being discharged in a high pressure; jet-like stream from between the pump gears adjacent the driven gear. When the pump gears receive a larger volume of oil than is discharged by them, an oil pressure between the pump gears is soon built up, causing them to stall to a varied extent on their respective axes. The extent of opening of gates 33 determines the amount of oilflow to the pump gears. On the amount of oil flow to the pump gears, the rapidity of oil discharge by the pumps and the resistance of the gear being driven, depends the degreeof oil pressure built up between the pump gears. Upon the degree of oil pressure built up between the pump gears, depends the amount of stalling of the driving gears and the ratio between the driving and driven gears. It will thus be seen that by properly adjusting the gates33, the flow of oil to the pumps may be regulated toeffect the driving of driven shaft 6 at tliedesired ratio of speed relative to the speed of the driving shaft 5. With any given adjustment of the gates -33, the speed of rotation of driven shaft 6 will automatically increase as resistance to its rotation is overcome or reduced.

From the foregoing description, it is believed that the construction and operation, as well as the advantages of the present invention will be readily understood and appreciated by those skilled in the art. While preferred embodiments of the invention have been illustrated and described in cons iderabledetail, itwill be apparent that'the invention is susceptible of modification and changes in details of construction such as fall within the spirit and scope of the invention as claimed. With the arrangement shown in Fi ure 11, the inertia of an idling engine can be used while driving on a down grade for braking purposes, the oil flowing to the pump gears transmitting momentum of the vehicle to the slowrunning engine so that only limited use of brakes is necessary. When the pedal 50 is not depressed, the arrangement results in free-wheeling. Also, by controlling the flow of oil to the gear pumps, the transmission functions as a clutch as well as to change speed. As a whole, the transmission also acts as a fly wheel.

What I claim is:

1. In a driving apparatus, a variable speed planetary type hydraulic transmission comprising, in combination with aligned driving and driven shafts, a housing having a pump chamber, means to secure said housing on the driving shaft for rotation with the latter, gear pumps arranged in said pump chamber at opposite sides of the housing and spaced apart to provide an oil space therebetween, each gear pump including intermeshing gears journaled for rotation relative to the housing upon axes parallel with the driving and driven shafts, a sun gear secured on the driven shaft and meshing with one gear of each pump, and swinging valve gates for controlling the flow of oil from said oil space to the respective pumps between both gears of each pump and the periphery of the housing, and manually operable means for operating said gates to regulate the opening or closing thereof.

2. In a driving apparatus, a variable speed planetary type hydraulic transmission comprising, in combination with aligned driving and driven shafts, a housing havin a pump chamber, means to secure said housing on the driving shaft for rotation with the latter, gear pumps in said pump chamber at opposite sides of the housing, each gear pump including intermeshing gears journaled for rotation relative to the housing upon axes parallel with the driving and driven shafts, a sun gear secured on the driven shaft and meshing with one gear of each pump, and swinging valve gates for controlling the flow of oil to the respective pumps at the periphery of the housing, a filler block on the periphery of the casing and extending inwardly between the outer portions of the gears of each pump, said pumps being spaced apart to provide an oil space between them, the gears of said pumps and the filler blocks being disposed to admit oil from said oil space to each pump with the oil flowing between the outer sides of both gears of each pump and the periphery of the housing in the direction of rotation of the pump gears.

3. The construction defined in claim 2, in combination with manually operable means for operating said gates to regulate the opening or closing thereof, said last-named means comprising rock shafts carrying said gates and projecting forwardly through the housing, laterally extending arms on the rock shafts, a spider longitudinally slidable on the driving shaft and having angular arms provided withrearwardly extending outer end portions, said rearwardly extending outer end portions being provided with forwardly converging, inclined slots receiving the free ends of said arms whereby rearward movement of the spider effects swinging of said arms in one direction to effect opening of said gates and forward movement thereof effects swinging of the. arms in the opposite direction to effect closing of said gates.

4. In a driving apparatus, a variable speed planetary type hydraulic transmission comprising, in combination with aligned driving and driven shafts, a housing having a, pump chamber, means to secure said housing on the driving shaft for rotation with the latter, gear pumps in said pump chamber at opposite sides of the housing, each gear pump including intermeshing gears journaled for rotation relative to the housing upon axes parallel with the driving and driven shafts, a sun gear secured on the driven shaft and meshing with one gear of each pump, and valve gates for controlling the flow of oil to the respective pumps at the periphery of the housing, said housing further having an oil supply chamber, and float means for automatically controlling admission of oil to the pump chamber from said supply chamber so as to maintain oil at a predetermined level in said [pump chamber.

5. The construction defined in claim 1, in combination with radial baffles in said oil space between the pumps and at opposite sides of the driven shaft.

6. In a driving apparatus, a variable speed planetary type hydraulic transmission comprising, in combination with aligned driving and driven shafts, a housing, a transverse partition dividing the housing into a pump chamber and a supply chamber, said partition having openings therein adjacent the periphery of the housing, means to secure said housin on the driving shaft for rotation with the latter, gear pumps in said pump chamber at opposite sides of the housing, each gear pump including intermeshing gears journaled for rotation relative to the housin upon axes parallel with the driving and driven shafts, a sun gear secured on the driven shaft and meshing with one gear of each pump, valve gates for controlling the flow of oil to the respective pumps at the periphery of the housing, float chambers in the supply chamber and communicating with the openings in the partition, and centrifugally-opened spring-closed float valves in said float chambers for automatically controlling passage of oil from the supply chamher to the float chambers so as to maintain oil at a predetermined level in said pump chamber.

GEORGE WALLACH. 

